Diabetic patients with chronic poor glycemic control may experience itching, ulcers and gangrene on the skin. Itching is mainly due to the patient’s high blood sugar, which stimulates the nerve endings causing neuropathy. This causes sensory dysfunction and itchy skin. At the same time also due to high blood sugar, vascular lesions may occur, which may easily lead to a decrease in blood flow to the lower limbs, resulting in a lack of supply of nutrients to the feet, so that the patient appears to have a decrease in skin temperature, intermittent claudication and so on, and in severe cases, ulcers and gangrene may occur, i.e., diabetic foot. In daily life, patients should take medication on time and not reduce or increase the dose of medication without authorization. Test blood sugar regularly and record it. Pay attention to personal hygiene and prevent infection. Adopt a balanced diet, food choices should be diversified and nutrition should be reasonable. If diabetic patients have the above symptoms, it is recommended to go to the hospital in time to avoid delay.